Embossment formation in press forging of AZ31 magnesium-alloy sheets

Embossment formation in press forging of AZ31 magnesium-alloy thin-walled structural components used in the electronics industry was examined by both the finite element analysis and the experimental approach in the present study. The mechanical properties of the AZ31 magnesium-alloy at elevated temperatures were first obtained from the compression tests under various strain-rates. The compression test results suggest that a feasible press forging process of AZ31 magnesium-alloy needs to be conducted at a forming temperature higher than 300 degrees C. The ring compression tests were also performed at various temperatures to obtain the friction factors at the die-blank interface under different lubrication conditions. The experimental results were then employed in the finite element simulations to investigate the effects of process parameters, such as punch shape and sheet thickness on the formation of embossments in a press forging process, and a modified punch shape was proposed to improve the efficiency of embossment formation according to the finite element analysis. Experiments of press forging of AZ31 magnesium-alloy sheets were conducted to validate the finite element analysis. Good correlations were observed between the finite element simulation results and the experimental data in all respects. The experiments conducted in the present study not only validated the finite element analysis but also confirmed the efficiency of the modified die design in helping the embossment formation. The mechanical properties of AZ31 magnesium-alloy at elevated temperatures and the detailed examination of the material flow on the formation of embossments made in the present study could provide a design guideline for a press forging process of AZ31 magnesium-alloy sheets.